Margin air flow doors for preventing pressure build up

ABSTRACT

Doors having stile and rail frames and center elements secured to the stile and rail frames and the center elements have margins inwardly where the center elements and the door frames overlap and openings extend through the margins outwardly from openings in skins, and inside and outside skins are secured to the stile and rail frames. The inside and outside skins have openings adjacent to and laterally or inwardly spaced apart from the openings through the margins whereby air flows through the openings in the inside skin, through the openings in the margins, and through the openings in the outside skin in a non-linear manner to prevent pressure build up in rooms to comply with the Department of Energy maximum recommended room pressure of three pascals or less.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 15/330,870, filedNov. 9, 2016, which is a continuation in part application of applicationSer. No. 15/330,471, filed Sep. 24, 2016, which was a continuation inpart application of application Ser. No. 14/999,148, filed Apr. 1, 2016,now U.S. Pat. No. 9,493,980, dated Nov. 15, 2016, a continuation in partof application Ser. No. 14/756,033, filed Jul. 23, 2015, and applicationSer. No. 14/756,017, filed Jul. 21, 2015, now U.S. Pat. No. 9,719,291,dated Aug. 1, 2017, which were continuation in part applications ofapplication Ser. No. 14/120,870, filed Jul. 7, 2014, now U.S. Pat. No.9,109,389, dated Aug. 18, 2015, and which was a continuation in partapplication of application Ser. No. 12/927,766, filed Nov. 23, 2010, nowU.S. Pat. No. 9,085,933, dated Jul. 21, 2015.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION Field of the Invention

This invention pertains to doors, and, more particularly, to doorshaving stile and rail frames and center panel elements and through whichmargin portions air flows in a non-linear manner for preventing thebuild up of air pressure a closed room.

Description of the Prior Art

Hollow core doors have been made for many years for inside doors. Thehollow core doors are less expensive than solid core doors, are easierto manufacture, and they are generally rigid and hence resist warpingand twisting. Such hollow core doors make up the largest share of insidedoors where strength and security are not required.

A hollow core door includes a conventional perimeter frame having a pairof vertically extending stiles and a pair of horizontally extendingrails. The perimeter frame is covered typically with plywood or otherappropriate panels or skins secured to the perimeter frame. There aregenerally also inside frame elements, typically wood strips extendinghorizontally between vertical frame members or in an “x” configurationwithin the perimeter frame for reinforcing the skins.

With the advent of cheaper materials, such as hardboard and mediumdensity fiberboard (mdf) to replace the plywood, the construction ofdoors became less expensive using the cheaper materials than themanufacture of doors using the more expensive plywood panels or skins.However, the use of hardboard and mdf also requires a binder, and themost commonly used binder is a urea formaldehyde resin or compound. Inother words, the substances out of which panels for hollow core doorsare made inherently include, under contemporary manufacturing processes,at least a single noxious material.

The use of urea formaldehyde contributes to what is sometimes referredto as “Sick Building Syndrome.” This syndrome is caused by the gasemissions from the formaldehyde and from other chemicals used in the newdoor products and from other products in the home that also useformaldehyde resin or binder, such as furniture, kitchen cabinets, woodflooring, counter tops, wallpaper, carpet, and even paint.

There may also be other factors contributing to the Sick BuildingSyndrome, such as poor ventilation, combustion gases, fumes fromattached garages, high auto traffic, tobacco smoke, and various volatileorganic chemicals or VOCs. However, formaldehyde compounds or productsprobably contribute most to the Sick Building Syndrome and to thediscomfort of people in the building or structure.

One solution, or partial solution, to the syndrome is to reduce the useof formaldehyde products. Another solution is to provide a product orproducts that absorbs and decomposes the formaldehyde gases and othernoxious gases or products. The present invention includes absorbentmaterial which absorbs and decomposes formaldehyde gases and othernoxious materials and removes them from within the hollow core door andfrom air passing through the hollow core of a door to help clean the airwithin the room and building in which the door is located.

Moreover, the use of several doors in a house or building, such as oneor more doors in each room, provides sufficient area on which isdisposed the absorbent material for cleaning or scrubbing the airflowing through the doors. It is noted that typically each room in ahouse has at least one door, and rooms may have more than one door whencloset doors, etc., are taken into consideration. The more doors in ahome or building, the more efficient the scrubbing or cleaning processbecomes.

It is also noted that in the case of new construction, doors are usuallyinstalled towards the end of the construction period, but prior tooccupancy. It is important to clean the air of all the noxious materialoccasioned by the construction, such as paints, adhesives, smoking, newfurniture, etc., prior to occupancy. The use of fans to change the airafter construction and prior to occupancy may remove much of the noxiousmaterials, but VOCs and adhesive gases may continue to outflow fromtheir sources for a substantial period of time after construction andafter occupancy. The present invention helps to remove those noxiousmaterials from the air on a continuing, long term basis.

Hollow core doors also have an advantage in that the hollow core isideal for including pressure equalization elements to prevent airpressure from building up within a closed room. Air pressure building upin a closed room interferes with the proper circulation of heated orcooled air in a forced air system.

The use of thinner skins in hollow core doors typically requires thatthe skins be molded for strength. A benefit of the molded skins isdecorative. That is, the molds are generally decorative to simulatewood. The thinner skins also require or need interior bracing of sometype. Openings in the skins at the margins, or adjacent to where theskins and the stiles and rails are aligned, allow air to flow throughthe door. Outer skins or baffle panels cover the openings to provide anon-linear path through the door for sight, sound, and light reductionor limiting purposes.

Stile and rail doors have a stile and rail frame and a center panel issecured to the frame. Typically, the stiles, rails, and the center panelare made of wood. Such stile and rail doors may also be used to preventpressure build up in a closed room.

Modifications to both hollow core and stile and rail doors may be madeto prevent pressure build up, whether the source of the pressure is froma forced air system or from ordinary wind through open windows.

Typically, there are no cost effective ways in the prior art to preventthe increase in pressure in a closed room relative to a return airspace. The return air space in a house is usually a hall which has areturn air duct which conveys return air back to an air handler.

Several embodiments of hollow core doors and stile and rail doors of thepresent invention overcome the problem of preventing pressure build upin a room and at the same time provide substantial privacy relative toboth light, sight, and sound. Moreover, the air scrubbing and pressurebuild up structures may be combined to provide a “smart door” thatperforms both a scrubbing function and a pressure build up preventionfunction.

SUMMARY

The invention described and claimed herein comprises doors having airflow, both hollow core doors with stiles and rails defining a frame andopenings through the outer margin of the hollow core door and openingsthrough the margin of the center panel and the stile and rail frames.Both types of doors have outer frames or skins defining baffles fordirecting air flow into and through the openings at the margins of thehollow core door and the stile and rail door and through the door in anon-linear manner. The air flow through the doors has at least fivechanges of direction to provide the non-linear flow of air through thedoor to prevent a build up of pressure in a room to which a door issecured. The flow of air through the openings at the margins is greaterthan the area of an inflow so that there is no build up of pressure inthe room. For a simple definition, the “margins” of the doors areadjacent to where the center elements of the doors meet the stile andrail frames. This definition will be discussed in detail below.

Among the objects of the present invention are the following:

To provide a new and useful hollow core door;

To provide a new and useful hollow core door having skins secured to astile and rail frame;

To provide a new and useful stile and rail door;

To provide a new and useful hollow core door having openings at themargins of the hollow core and the stiles and rails;

To provide a new an useful stile and rail door having openings at themargins of the stiles and rails and a center panel;

To provide a new and useful door having air flow through the margins ofthe door of a predetermined amount equal to or greater than the air flowinto the room to prevent the build up of pressure in the room;

To provide a new and useful door having a stile and rail frame andcenter elements secured to the stile and rail frame and having openingsat the margins of the center elements and the stile and rail frame and acover element secured to the stile and rail frame to provide an air flowthrough the margin openings in the door in a non-linear manner toprevent pressure build up in a closed room;

To provide a new and useful hollow core door having openings in themargins of the skins and outer skins having openings adjacent to themargin openings through which a flow of air moves through the door in anon-linear manner;

To provide a new and useful hollow core door for preventing a build upof pressure in a room by air flowing non-linearly about a center panelthrough the door;

To provide a new and useful hollow core door having center elements withopenings at the margins of the center elements through which air flowsand outer skins having an opening adjacent to the openings at themargins for directing the flow of air through the door in a non-linearmanner;

To provide a new and useful door combining an air flow through the doorfor removing noxious materials from the air flow and for preventing apressure build up in a room by flowing air generally non-linearlythrough the door to a return air space;

To provide new and useful apparatus for preventing a build up ofpressure in a closed room having a forced air system;

To provide a new and useful stile and rail door having a center elementsecured to the stiles and rails and openings at the margins of thestiles and rails and the center element through which openings air flowsand a cover element through which air flows; and

To provide a new and useful stile and rail door having a center panelwith openings at the margins of the stiles and rails and the centerpanel and skins secured to the stiles and rails having openings adjacentto the openings at the margins for providing non-linear movement in aflow of air through the door.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic representation of a door of the present inventionin its use environment.

FIG. 2 is a perspective view of a portion of the door of FIG. 1partially broken away, taken generally from circle 2 of FIG. 1.

FIGS. 3, 4, and 5 are perspective views sequentially illustrating themanufacture of a door of the present invention.

FIG. 6 is an end view of a hollow core door of the present invention.

FIG. 7 is a schematic representation, including a view in partialsection of an alternate embodiment of a portion of a door 410 of thepresent invention illustrating core elements, in the use environment ofthe present invention.

FIG. 8 is an exploded view of a portion of the door 410 of FIG. 7.

FIG. 9 is a fragmentary view, partially broken away, of a portion of analternate embodiment door 620 of the present invention.

FIG. 10 is a fragmentary edge view of a portion of the door 620 of FIG.9.

FIG. 11 is a perspective view partially broken away schematicallyillustrating an alternate hollow core door embodiment 650 of the presentinvention.

FIG. 12 is a schematic view in partial section taken generally alongline 12/13-12/13 of FIG. 11.

FIG. 13 is a schematic view in partial section sequentially followingFIG. 12 also taken generally along line 12/13-12/13 of FIG. 11.

FIG. 14 is a view of the door apparatus of FIG. 11 taken generally alongline 14-14 of FIG. 12.

FIG. 15 is a view of the apparatus of FIG. 11 taken generally along line15-15 of FIG. 13

FIG. 16 is a fragmentary view of a portion of the door 650 apparatus ofFIG. 11.

FIG. 17 is a fragmentary front view, partially broken away, of analternate embodiment hollow core door 750 of the present invention.

FIG. 18 is an enlarged schematic view in partial section taken generallyalong line 18-18 of FIG. 17.

FIG. 19 is a schematic view of a portion of a prior art stile and raildoor having a perimeter air flow.

FIG. 20 is plan view, partially broken away, of the upper portion of aprior art hollow core door with movable damper panels for controllingair flow through the door.

FIG. 21 is a schematic view in partial section and partially broken awayillustrating the structural elements and the movable damper panels ofthe present invention, taken generally along line 21-21 of FIG. 20.

FIG. 22 is a plan view, partially broken away, of a hollow core doorembodiment of the present invention.

FIG. 23 is a view in partial section taken generally along line 23-23 ofFIG. 22.

FIG. 24 is a view in partial section taken generally along line 24-24 ofFIG. 22.

FIG. 25 is a plan view, partially broken away, of a stile and rail doorembodiment of the present invention.

FIG. 26 is a view in partial section taken generally along line 26-26 ofFIG. 25.

FIG. 27 is a view in partial section taken generally along line 27-27 ofFIG. 25.

FIG. 28 is a view in partial section of another embodiment of a hollowcore door of the present invention.

FIGS. 29, 30, and 31 are fragmentary plan views of doors of the presentinvention illustrating examples of decorative geometric designs for thedoors.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Only the pertinent drawing figures of the parent applications of thepresent invention are included herein. Except for FIGS. 1-6, the figurenumbers have been changed from the original applications, but thereference numerals for the original figures have been retained forconvenience.

FIG. 1 is a schematic representation of a view of a conventionallyframed hollow core door 10 of the present invention disposed in a room3. The room 3 is the use environment of the door 10. The door 10includes a top panel or skin 12 (see FIG. 2) secured to a perimeterframe

Elements of the perimeter frame and portions of internal elements areshown in FIG. 2. FIG. 2 comprises a perspective view of a portion of thedoor 10 of FIG. 1, taken generally from circle 2 of FIG. 1. A portion ofa side stile 12 is shown, along with a portion of a top rail 16, and atop panel or skin 40. The top rail 16 includes a plurality of openingsor holes 18 through which air flows vertically within the door 10. Alsoshown in FIG. 2 is a portion of an upper internal brace element 24. Theelement 24 includes a plurality of spaced apart holes or openings 26through which air may flow.

The door 10 and a method of making the door is illustrated in FIGS. 3,4, and 5. FIGS. 3, 4, and 5 are consecutive or sequential perspectiveviews illustrating the steps used to make the door 10. FIG. 5 alsoillustrates the internal bracing of the door 10. FIG. 6 is an end viewof the completed door 10. For the following discussion, reference willbe primarily directed to FIGS. 3, 4, 5, and 6.

A central portion 52 of an outer door panel or skin 50 may be roughsanded by a belt sander 2 after parallel rabbets 54 and 56 are machinedinto the panel 50. Obviously, an automatic sanding machine, not shown,may be preferable to the hand operated belt sander 2 shown in FIG. 3 ifsuch sanding is deemed desirable. The purpose of the sanding is toacquire better adhesion of absorbent material to the panels of the door.Other methods may also be used, such as paint or other adhesive.

The stiles 12 and 14 extend into the rabbets 54 and 56, as best shown inFIG. 6, when the outer panels are ready to be secured to the perimeterframe and to any internal frame elements.

After the rough sanding or sealing of the panel, an absorbent, such asdiatomaceous earth, is applied to the rough sanded portion 52 of thepanel 50. In FIG. 4, the absorbent material is schematically representedby reference numeral 60 being applied from a can or cup 4 or otherdesired element to form a layer on the sanded portion 52 of the panel50.

It will also be noted that paper impregnated with an absorbent materialmay also be adhesively secured to the panel portion 52. Paper strips aresometimes adhesively secured to the inside portions of the outer panelsor skins to provide stiffness. The strips may be impregnated with anabsorbent, as noted.

The layer 60 is a special absorbent material which also may include anappropriate binder to secure the adhesion of the absorbent material tothe panel 50. A water based paint may be used if desired. A scraper ortrowel 6 is shown in FIG. 4 as smoothing the layer of absorbent material60 on the panel 50 to insure an even coating on the panel.

It will be noted that any appropriate method of applying the absorbentmaterial may be used. For example, rollering, spraying, troweling, etc.,may be desired under various circumstances, such as when automating theprocess, or when a particular type of absorbent material used, etc.

Absorbent materials, such as diatomaceous earth and other materialswhich may also contribute to the absorption and decomposition offormaldehyde and noxious material may be includes in the absorbentmaterial layer 60. A benefit of using diatomaceous earth, in addition toits absorbent capability, is the destruction of noxious insects. It iswell known that insects which eat diatomaceous earth die of dehydration.Thus, the absorbent material layer 60 provides a pest control service orfunction, in addition to the absorption and decomposition offormaldehyde gases and tobacco smoke ingredients, and other noxiousgases.

Other materials such as gypsum, sodium sulfate, manganese dioxide,aluminum oxide, titanium dioxide, potassium permanganate, tourmaline,various types of carbon or charcoal, and other materials currently beingused or being developed may also be included or used as or in theabsorbent material layer 60.

Furthermore, the use of nano scale materials may also be used to scrubnoxious materials, such as volatile organic chemicals (VOCs), from air.Nano scale materials, such as the tourmaline referred to in thepreceding paragraph, are being developed for scrubbing noxious materialsfrom air, but at the present time the use of such technology is in itinfancy. In the future, such materials may be advantageous for use withthe structure set forth herein.

The steps illustrated in FIGS. 3 and 4 are accomplished on the innersurfaces of both panels or skins 40 and 50. Sequentially, after bothpanels have received the absorbent or scrubber material, the panels aresecured to the perimeter frame and to the internal bracing or core. Forexample, in FIG. 5 the bottom panel 50 is shown secured to the stiles 12and 14 and to the rails 16 and 20. Both rails 16 and 20 include theholes or apertures 18 and 22, respectively. Internal horizontal bracingor core elements 24, 28, and 32 are secured to the panel 50 and to thestiles 12 and 14. The elements 24, 28, and 32 each have a plurality ofholes or apertures 26, 30, and 34, respectively, to allow for the flowor air continuing through the core of the door 10.

FIG. 6, an end view of the door 10, shows the stiles 12 and 14 and thebottom rail 20 with its apertures 22, and the panels or skins 40 and 50.Note that the panels or skins 40 and 50 have been arbitrarily beendesignated “top” and “bottom” for convenience. The “top” panel 40 orskin is also designated as the “front” panel, above, and following thenomenclature of the parent applications except for the ultimate parentapplication, the '933 patent, comprises the inside skin.

Moreover, if absorbent and decomposing materials, such as diatomaceousearth and gypsum, etc., are incorporated into the construction of themdf or similar material, then such materials need not be added to theinside of the panels themselves. Rather, the addition of the scrubbingmaterials to the mdf or similar material in the making of the panelssimplifies the scrubbing situation.

However, the inclusion of the scrubbing materials into the panels maynot be sufficient if the filtering or scrubbing of an air flow through ahollow core door is desired. In such case, the addition of scrubbingmaterial or materials within the hollow core as described above isdesirable.

While diatomaceous earth and other materials have been mentioned ordiscussed above as appropriate absorbent materials for formaldehyde andother noxious material in the gases in the air flowing through thehollow core of a door, there are other appropriate absorbent ordecomposing materials, such as activated carbon or charcoal, withappropriate additives, and other materials which also may be used forabsorbing and decomposing formaldehyde and other noxious gases in theair flowing through the internal core of the hollow doors discussedabove. And in the future there will undoubtedly be other materials toperform the same basic scrubbing functions.

Moreover, one panel or skin, a top panel or skin for example, may useone type of absorbent or decomposing material, while the other panel orskin, a bottom panel or skin, may use another type of absorbent ordecomposing material. Or several types of such materials may be used oneach panel or skin. The use of a particular one or more materials maydepend on the particular situations or locations for or at which thedoors are made or are installed. The removal of noxious materials fromair flowing through the hollow core of a door may include differenttypes of absorbent or decomposing or other products. Noxious materialmay take the form of compounds, odors, moisture, etc., and combinationsof such things.

The removal of such noxious material may require absorption,decomposition, or other technique—chemical, mechanical, etc. The flow ofair in a structure and through the hollow core of a door carries thenoxious material, and the removal of the noxious material may require acombination of products, techniques, etc.

Another technique may also be used to remove noxious materials, and thattechnique is to use a photocatalyst, such as titanium dioxide. Aphotocatalyst, such as titanium dioxide reacts to light, such as ultraviolet light, and breaks down into hydroxyl radicals and super oxideanions. The products of the photocatalytic process oxidize noxiousmaterials, such volatile organic compounds, formaldehyde, and othermaterials as referred to above, etc.

Ambient light, direct sunlight, or an artificial light source, may beused to provide the necessary light to catalyze the photocatalyticmaterial. The photocatalytic process will continue as long as there islight to cause the photocatalytic process to take place.

Accordingly, referring to FIG. 1, the exterior of the door, or the doorfacings, may be coated with titanium dioxide or other photocatalyticcompound. In the presence of light, sunlight or ambient light, thephotocatalytic process takes place, removing noxious products ormaterials.

It will be noted that the term “gases” is to be broadly construed andincludes water vapor or moisture in the air, as well as odoriferousgases, and other noxious materials or compounds in the air within astructure. The term “gases” is thus not limited to formaldehyde orsimilar gases.

It will also be noted that doors made out of mdf products have beendiscussed and illustrated because of the use of formaldehyde resin orbinders commonly used in the manufacture of mdf products, andformaldehyde is probably the leading noxious material. However, a hollowcore door made of steel, fiberglass, wood, or other products, may alsobe used with absorbent, decomposing, etc., material within the hollowcore for removing or neutralizing noxious material or products or gasesfrom air flowing through the hollow core. The scrubbing of noxiousmaterial from air flow accordingly may require a combination ofmaterials secured within the hollow core of a door regardless of whatthe door is made of.

The terms “scrubber,” “scrubbers,” and “scrubbing,” all refergenerically to the various kinds or types of material which may be usedto remove noxious materials from the internal air flow within the coreof a door.

It will further be noted that as used herein, and in the followingclaims, the terms “material” and “materials” are virtuallyinterchangeable, with “material” being considered both, or either,singular or plural.

The terms “absorb” and “absorbent,” etc., have been used hereinregarding appropriate materials for carrying out the purposes of thepresent invention. It will be understood that “adsorb” and “adsorbent”materials may also be used to carry out the purposes of the presentinvention. Essentially, for purposes herein, the terms areinterchangeable. Moreover, it will be understood that a combination ofabsorbent and adsorbent materials may be used if desired in the cleaningor filtering of the air flow through the hollow core doors of thepresent invention.

In addition to the removal of noxious material from an air flow throughhollow core door, a hollow core door may be used to prevent the build upof air pressure in a closed room which has a forced air system.Embodiments of such hollow core door apparatus are illustrated indrawing FIGS. 7-18 are discussed below. An embodiment of a stile andrail door is illustrated in FIG. 19 and is also discussed below.

FIG. 7 is a schematic view in partial section of a portion of a door 410illustrating the concept of the present invention in an embodiment forpreventing the build up of air pressure from a flow of air 404 flowingfrom a register 402 in a closed room 404.

FIG. 8 is an exploded perspective view of a portion of the apparatus ofFIG. 7. For the following discussion, reference may be made to bothFIGS. 7 and 8.

The register 402 provides a flow of air 404 into the closed room 400.The air flow into the room 400 is measured in cubic feet per minute(CFM). To prevent a build up of pressure in the room 400, the flow ofair through the door 410 to a return air space 434 outside the room 400should be proportional to the CFM flow of the inflow air 404. This willbe discussed in more detail below on conjunction with the structure ofthe door 410.

It will be noted that in the doors in this application the terms“inside” and “outside” refer to the room in which the doors areinstalled. The “inside” refers to the inside of the room 400 and the“outside” refers to the side of the door 410 which faces outwardly fromthe room and is in contact with the return air space 434.

The door 410 includes an inside door panel or skin 412 comparable to thepanel or skin 50 as may be best understood from FIGS. 3-6. The panel orskin 412 is appropriately secured to a top rail 411 and to a horizontalbracing element 413. The top rail 411 is comparable to the top rail 16of FIG. 5, and the element 413 is broadly comparable to the bracingelement 28 of FIG. 5. A single stile 415 is shown in FIG. 7.

The construction of the door 410 is typical of hollow core doors otherthan the air flow refinements of the air flow elements. Extendingthrough the inside door skin 412 is an opening 414. The opening 414 maybe rectangular, or circular, etc. In the opening 414 is an inner panel440. The configuration of the panel 440 is generally the same as that ofthe opening 414. The air flow 404 from the register 402 flows throughthe opening 414 and about the inner panel 440 and into an intake airspace 416.

The door 410 also includes an outside door panel or skin 430, comparableto the panel 40, as may best be understood from FIGS. 2 and 6. The doorpanel or skin (generally “skin” or “skins” hereafter) 430 includes anopening 432 which is generally parallel to the opening 414 and issubstantially the same size as the opening 414. Disposed in the opening432 is an outer panel 450. The outer panel 450 is generally parallel tothe inner panel 440 and is substantially the same size.

Between the door skins 412 and 430 is a center panel 420. The centerpanel 420 includes a plurality of openings 422. Adjacent to the openings422 on the opposite side of the center panel 420 and between the centerpanel 420 and the outer panel 440 is an outflow space 424. The outflowspace 424 is generally parallel to the intake space 416 and issubstantially the same size.

The inner panel 440 includes an outer periphery or rim 442, and theouter panel 540 includes an outer periphery or rim 452. Between thepanel 440 and the center panel 420 is a plurality of spacers 444.Between the outer panel 450 and the center panel 420 is a plurality ofspacers 454. The spacers 444 and 454 secure the panels 440 and 450,respectively, to opposite sides of the center panel 420, andappropriately space the center panel 420 from the inner and outer panelsto define the size of the intake space 416 and the size of the outflowspace 424. The spaces 416 and 424 have the same area.

It will be noted that the spacers 444 and 454 are shown in FIG. 7 asbeing rectangular or circular in configuration, and in FIG. 8 as beingtruncated pyramidal in configuration. The configuration of the spacersis immaterial; they may be of any desired or convenient configuration.

It will be noted that there are two peripheral spaces shown in FIG. 7There is a first or inside peripheral space between the opening 414 andthe rim or outer periphery 442 of the inner panel 440, and through whichthe air flow 404 flows into the space 416. There is a second, or outerperipheral space between the opening 432 and the rim or outer periphery452 of the outer panel 450 through which the air flow 406 flows orpasses to the return air space 434.

There is a smooth flow of air 404 from the register 402 through theperipheral space about the rim 442 of the inner panel 440 within theopening 414 into the intake space 416. The air then flows through theopening 422 in the center wall 420 to the outflow space 424 andoutwardly through the peripheral space about the rim 452 of the insidepanel 450 in the opening 452, and becomes an air outflow 406 to thereturn air space 434 outside the room 400, thus preventing the build upof air pressure in the room 400.

The peripheral spaces of the inside panel 440 and the outside panel 450and the size or area of the openings 422 are appropriately dimensionedto provide at least the same or greater area than the peripheral spaces.The air flow 404 thus has no constraints to flowing non-linearly throughthe door 410 and outwardly from the room 400 into an air return space434 outside the room 400.

Thus there is no build up of pressure within the room 400. That is, theair flow out of the room 400 through the door 410 is proportional to theCFM of the flow of air through the register 402 into the room 400. Thedoor 410 thus prevents the build up of pressure in the room 400.

The areas through which the air flows must provide an area proportionalto the CFM of the inflow of air through the register 402. There is arelationship between the CFM of the inflow 404 and the square inches ofthe areas through which the air flows. For example, for a 90 CFM inflow404, there should be an area of about 90 square inches through which theair flows through the peripheral space between the opening 416 and therim 442 into the space 416, and there should be at least the same 90square inches in the openings 422 for the flow of air from the space 416into the space 424. There also should be the same 90 square inches forthe air flow 406 through the peripheral space between the opening 432and the rim 542.

The distances between the outer periphery or rim 442 and the opening414, and between the outer periphery or rim 452 and the opening 432, aresubstantially the same. Those distances, and the length of the spacers444 and 454, are dimensioned so as to provide the same CFM through thedoor 410 as the CFM through the register 402 of the air flow 404. Thatis, the spacing between the rim 452 and the opening 432 defines aperipheral space to provide the desired area for the desired air flow,and is thus equal to the peripheral space between the opening 414 andthe rim 442 of the panel 440.

The square inches discussed above are the minimum areas for the CFM ofthe air flow through the register 402 into the room 400 and through thedoor 410 for the out flow 406 into the receiving space 434 to preventany increase in the air pressure in the room 400. However, the squareinches may be larger if the door permits. On the other hand, dependingprimarily on the thickness of the door, providing the necessary squareinches for the air travel through the door may require additionalelements, such as slanted panels into the air spaces 416 and 424. Thiswill be discussed below.

In terms of pressure, professional standards, such as Energy StarCertified Homes, and the DOE's Zero Energy Ready Home Program, generallyconsider that the pressure in a closed room should be less than 3pascals, or about 0.012 inches of a water column. For larger rooms, thepressure rises to equal to or less than 5 pascals. The present inventionmeets those criteria.

In FIG. 7, the panel 440 is shown disposed in the opening 414, and thepanel 450 is shown disposed in the opening 432. However, it will beunderstood that the panels 440 and 450 will be spaced apart from theirrespective skins 412 and 430 in or adjacent to the openings 414 and 432,respectively, to provide the necessary peripheral spacing relative tothe intake spaces 416 and 424, respectively, to provide the desired airflow.

For example, for a relatively strong air flow, in terms of CFM, and arelatively narrow door, the spacing of the panels may be outwardly fromthe door skins to provide the required peripheral spacing, or in arelatively weak air flow, and a relatively thick door, the panels may bedisposed inwardly from the door skins. Thus, the term “adjacent” may beused to define the relationship between the door skins and theiropenings and the locations of the panels relative to the openings in thedoor skins. The term “adjacent” accordingly denotes the positioning of apanel relative to the openings in the skins in, inside, or outside, theopenings.

In FIG. 8, a plurality of openings 414 are shown in the center panel420. The total area of the openings 414 is equal to or greater than thearea in square inches as discussed above.

FIG. 9 is a fragmentary view, partially broken away, of a door 620 whichcombines the air scrubbing capabilities of the embodiments of FIGS. 1-6with the air pressure build up prevention by non-linear air flowcapabilities of the door 410 of FIGS. 7 and 8. FIG. 10 is a fragmentaryedge view in partial section of a portion of the door apparatus of FIG.9.

The door 620 includes a stile 622 and a rail 626. The door 620 is shownwith an outside skin 628. A portion of the outside skin 628 is brokenaway to show details of the stile 622.

The stile 622 is split to provide an air passage into the hollow coreinterior of the door 620. As may be understood best from FIG. 10, thestile 622 is split and the two portions are spaced apart by a pluralityof dowels 632 and includes a passageway 624 vertically through thestile. A passageway 624 between the two portions of the stile allows airto flow laterally through the stile into the hollow core portions of thedoor. Scrubbing elements for removing noxious material, as discussedabove for the embodiments of FIGS. 1-6, may remove the noxious materialfrom the air flow.

Similarly, the rail 626 may also be split as shown in FIG. 10 bysubstituting the reference numeral 626 for the reference numeral 622 inFIG. 10. The rail 626 uses dowels 632 to space apart the two portions ofthe rail. With split stiles and rails about the perimeter of the door,including reinforcing rails between the top and bottom rails, and holesthrough the bottom rail, as shown and discussed above in conjunctionwith the embodiments of FIGS. 1-8, and with the scrubbing material alsodiscussed therewith, air flow through the door 620 performs airscrubbing functions, as well as preventing the build up of air pressurein a closed room when appropriate elements, such as the apparatus 410,are installed in the door.

The pressure of the flow of air into a room, such as the flow 404 of theroom 400 of FIG. 7, will provide an air flow through the door 620 to areturn air space and also through the stiles and rails for a scrubbingaction. Air will thus flow through the door to prevent the build up ofpressure and through the stiles and rails to the interior hollow corefor the air flow to be scrubbed of noxious materials.

The doors 410 and 620 comprise first generation hollow core doors forpreventing pressure buildup in a room, a hollow core door 650 comprisesa second generation door, and a first generation “smart door.” The door650 includes privacy provisions and the ability to control the flow ofair through the door incrementally from full flow to non-flow, alongwith the ability to control various programmable electronic devices in aroom or structure. Moreover, the door 650 provides a degree of fireretardant capability that provides time for room or house evacuation notprovided by standard or contemporary interior hollow core doors, as willbe explained below.

FIG. 11 comprises a schematic fragmentary perspective view, partiallybroken away, of the hollow core door 650. The hollow core door 650includes a top rail 652 secured to a stile 654. The top rail 652 and abottom rail, not shown, the stile 654, and another stile, also notshown, comprise a conventional frame for the hollow core door 650.

The door 650 includes an inside skin 660 and an outside skin 720, bothof which are shown secured to the top rail 652 and to the stile 654. Theoutside skin 720 includes an opening 712. The opening 712 includes aninner periphery 714. An outside panel or privacy panel 720 is disposedin the opening 712. The panel 720 includes an outer periphery 722 whichis disposed in the opening 712. A peripheral space 718 is definedbetween the outer periphery of the panel 720 and the inner periphery 714of the opening 712.

Within the hollow core door 650 is a pair of fixed panels 680 and 700,both of which are secured to the stile 654. A sliding panel 690 isdisposed and movable between the fixed panels 680 and 700.

An actuator 730 is appropriately secured to the slidable panel 690. Theactuator 730 is shown disposed within the stile 654. A sensor 740 isalso disposed within the stile 654. The sensor 740 senses predeterminedor desired information from the air adjacent to the door 650. Suchinformation may include temperature, pressure, smoke particlesindicative of a fire, carbon monoxide, relative humidity, or otherdesiderata. The sensor may provide and transmit signals in response tothe desired sensed information. Signal outputs from the sensor may besensed by the actuator 730 and by other electronic elements in the roomor structure in which the door 650 is installed.

An output signal from the sensor 740 may result in the actuator 730moving the slidable panel 690. Such movement may be sequential andincremental or full, as described below. Other signals may turn on oroff lights, adjust blinds, etc., such as are now provided by smartphones and other electronic devices. Essentially the door 650, with thesensor 740, becomes an intelligence center for the room or structure inwhich the door is installed, with the ability to provide desired outputsignals to a wide variety of programmable electronic devices.

FIGS. 12 and 13 are schematic views in partial section taken generallyalong lines 12/13-12/13 of FIG. 11 through the door 650. FIG. 13 followssequentially after FIG. 12. FIGS. 12 and 13 illustrate the movement ofthe sliding panel 690 relative to the fixed panels 680 and 700.

For the following discussion, reference may be made particularly toFIGS. 12 and 13, but also to FIG. 11. Note that movement of the slidingpanel 690 is into and out of the pages for the FIGS. 12 and 13.

Spacer blocks 656 and 716 separate the skins 660 and 710 from the fixedpanels 680 and 700, respectively.

The inside skin 660 includes an opening 662, and the opening 662 has aninner periphery 664. Within the opening 662 is an inside panel orprivacy panel 670. The panel 670 has an outer periphery 672. Aperipheral space 666 is formed between the inner periphery 664 of theskin 660 and the outer periphery 672 of the privacy panel 670.

The panel 670 is spaced apart from the fixed panel 680 by a plurality ofspacers 674. An interior space 686 is defined between the fixed panel680 and the skin 660 and its privacy panel 670. Air flows into the space686 through the peripheral space 666. Note that the thickness of thespacer block 656 is the same as the length of the spacers 674.

The fixed panel 680 includes a plurality of openings. Air flow from thespace 686 is through the openings 682.

The movable or slidable panel 690 is disposed between the fixed panels680 and 700. The panel 690 includes a plurality of spaced apart openings692. The openings 692 are shown aligned with the openings 682 of thefixed panel 680 in FIG. 14.

The fixed panel 700 includes a plurality of spaced apart openings 702.The openings 702 are shown aligned with the openings 682 of the fixedpanel 680.

As stated above, the outside skin 710 includes an opening 712, and theopening 712 includes an inner periphery 714. The privacy or outsidepanel 720 is disposed in the opening 712, and has an outer periphery722. A peripheral space 718 is defined between the inner periphery 714of the outside skin 710 and the outer periphery 722 of the privacy panel720. The panel 720 includes a plurality of spacers 724 to space apartthe panel 720 from the fixed panel 700.

The outside or privacy panel 710 is spaced apart from the fixed panel700 by a spacer block 716. The spacer block 716 has the same thicknessas the spacers 724 of the panel 720. The spacer blocks 656 and 716 havethe same thickness, and the spacers 674 and 724 also have the samethickness or length.

A chamber 706 is defined by the fixed panel 700 and the skin 710 and itsprivacy panel 720. Air flows from the chamber 706 outwardly through theperipheral space 718. When the openings 682, 692, and 702 are aligned,as shown in FIG. 24, air flows from the chamber 686 into the chamber706.

The combined areas of the openings 682, the combined areas of theopenings 692, and the combined areas of the openings 702 are equal toeach other.

The openings 662 and 712 (see FIGS. 11 and 12) are the same size. Thesize or area of the panels 670 and 720 are also the equal to each other,and accordingly the peripheral spaces 666 and 718 have the same areas.Therefore, the same amount of air will flow into the chamber 686 as mayflow through the aligned openings in the fixed and sliding panels andout of the chamber 706. As with the doors of FIGS. 7-10, the respectiveareas provide proportional areas for the airflow through a register intoa room and out of the room through the door 650 to prevent the build upof pressure in the room.

When the openings 682 and 702 are blocked by movement of the slidingpanel 690, as shown in FIG. 15, there is no flow of air between thechambers 686 and 702. The panel 690 is moved by the actuator 730, asshown in FIGS. 14 and 15.

FIGS. 14 and 15 are schematic views in partial section takenrespectively along lines 14-14 and 15-15 of FIGS. 12 and 13. FIGS. 14and 15 show sequentially the movement of the sliding panel 690 fromaligning the openings 682, 692, and 702 to allow for the flow of airthrough the fixed and slidable panels between the chambers 686 and 706and to the complete blocking of the air flow by a complete misalignmentof the openings 682 and 712 in the fixed panels 680 and 700,respectively, by movement of the sliding panel 690, as shown in FIGS. 13and 15.

There is airflow shown in FIG. 14, and there is no airflow shown in FIG.15. Airflow is allowed by the alignment of the openings 682, 692, and702 shown in FIG. 14, and airflow is blocked by moving the panel 690 sothat the opening 692 is out of alignment with the openings 682 and 702in FIG. 15. Note that airflow in and through the door 650 is non-linear,as with the doors 410 and 620, discussed above.

The actuator 730 moves the slidable panel 690 in response to a signalfrom the sensor 740 or from manual signal from a user or occupant of theroom in which the door 650 is installed. There is no significant flow ofair through the door 650 when the openings 692 are out of alignment withthe openings 682 and 702. With a programmable sensor 740, the movementof the panel 690 may be set to incrementally move the panel 690 inresponse to a temperature change, or other criteria, to a full closingor misalignment of the openings as shown in FIGS. 13 and 15, as desired,or to a full opening by a full alignment of the openings as shown inFIGS. 12 and 14.

A full closure or non-movement of air through the door 650 by completenon-alignment or blockage of alignment of the openings in the fixed andmovable panels as shown in FIGS. 13 and 15, may also be obtained by thesensing of a fire by the sensor 740. Such full closure or blockageprovides three panels on the interior of the hollow core door 650. Theadditional fire resistance may provide additional time for occupants toevacuate the structure in which the door/doors is/are installed. Thefull non-alignment of the openings in the panels 680, 690, and 700 mayalso restrict the availability of air or oxygen to a fire in the room.

As stated above, the programmable functions available in contemporaryelectronics make the door 650 a “smart door” with many capabilities. Thelocation of the sensor 740 in a stile at an appropriate height allowsthe sensing of information whether the door 750 is open or closed, oranywhere in between, and the sensing is to a more accurate degree thanthat of a fixed sensor on a wall or on a ceiling. Thus, a plurality of“smart doors” in a structure provides more accurate and more completeinformation relative to individual rooms and halls than contemporaryfixed wall or ceiling sensors may provide.

However, it will be noted that a sensor need not be installed as shown.If desired, a sensor may be installed in any desired of appropriatelocation in a room, such as wall mounted sensor/transmitter 403 shown inFIG. 7. Nevertheless, the advantages of the sensor installed in the doorappear to be preferable to a wall or ceiling installation.

Another advantage or benefit of being able to prevent air flow through adoor is when there is a need to limit contact with an individual with amedical problem transmissible by close contact through air flow, such ascolds, flu, etc. The person with such medical problem may be isolated ina limited manner by preventing air flowing from the room as providedabove. Opening a window in the room may provide sufficient fresh air,and an open window may help evacuate contaminated air from the room.

FIG. 16 is a fragmentary view in partial section of a portion of thedoor 650 illustrating the support for the sliding panel 690 on the fixedpanel 680. The fixed panel 680 includes a plurality of spaced apartguide blocks 684. The slidable panel 690 includes a plurality of slots694 which receive the guide blocks 684. The sliding or movable panel 690is thus supported by and is movable on the guide blocks 684 of the fixedpanel 680.

The full pressure build up prevention capabilities of the embodiments ofFIGS. 7-16, and the scavenging or scrubbing properties of theembodiments of FIGS. 1-6, may be included in the embodiment of the“smart door” of FIGS. 11-16, thus providing multiple capabilities andbenefits.

The non-linear flow of air may be provided in another embodiment, athird generation hollow core door 750, illustrated in FIGS. 17 and 18.There is less privacy with the door 750, but there may be greater airflow through the door 750.

FIG. 17 is a partial front or plan view of a portion of the hollow coredoor 750 having a non-linear flow of air through the door. Portions ofthe door 750 are broken away to shown structural and other features ofthe door. FIG. 18 is a view in partial section of a portion of the door750 taken generally along line 18-18 of FIG. 17. The door 750 includes afixed center panel disposed between the inside and outside skins. Forthe following discussion of the door 750, reference may be made to bothFIGS. 17 and 18.

It will be noted that the terms “inside” and “outside” are used withrespect to the door 750 as set forth above with respect to the doors410, 620, and 650.

The door 750 includes a conventional hollow core door perimeter frame752, including a pair of stiles 754 and 758 and a pair of rails 760 and762 appropriately secured together. The stile 754 has an end face 756,shown in FIG. 18.

An inside skin 770 is secured to the frame 752. The inside skin 770includes a rabbet 772 and a shoulder 774 at the end of the rabbet 772. Amating shoulder of the stile 754 is disposed against the shoulder 774.The inside skin 770 also includes a recess or bore 776, and an opening778. The opening 778 frames a fixed center panel 790. The opening 778 isshown as rectangular in FIG. 17, but may be any desired configuration toconform to a panel which is generally centered or framed by the opening778. The opening 778, as best may be understood from FIG. 17, defines aninner periphery for framing the panel 790.

The panel 790 is illustrated as being generally rectangular as indicatedby the solid and dotted line in FIG. 17. The panel 790 includes an outerperiphery 792. The opening 778, or its inner periphery, is smaller thanthe outer periphery 792 of the panel 790. The area between the innerperiphery of the opening 778, and of a like opening 788 in an outsideskin 780, and the outer periphery 792 of the panel 790, defines aperimeter portion of the door 750 where the panel is secured to theinside and outside skins, as discussed below and as shown in FIG. 18.

The outside skin 780 includes a rabbet 782 with a shoulder 784 againstwhich a mating shoulder of the stile 754 is disposed. The outside skin780 also includes a recess or bore 786 aligned with the bore 766 of theinside skin 770. The opening 788 is aligned with the opening 778 of theinside skin 770. The recesses or bores 776 and 786 are also aligned witheach other.

The inside skin 770 and the outside skin 780 are mirror images of eachother, and they frame the panel 790. The panel 790 is disposed betweenand spaced apart from the two skins.

The center panel 790 is secured to the inside and outside skins 770 and780, respectively, by spaced apart support blocks 800. In FIG. 17, thesupport blocks 800 are shown in dotted line spaced apart for supportingthe panel 790. The recesses 766 and 786 in the skins 760 and 780 receivethe support blocks 800. As may be understood from FIG. 17, there are aplurality of spaced apart and aligned recesses or bores 776, 786 forreceiving a plurality of support blocks 800.

The support blocks 800 include recesses or slots 802. The recesses orslots 802 extend inwardly from the support blocks 800 and receive theouter periphery 792 of the panel 790 to secure the panel between theinside and outside skins. The recesses 802 of the support blocks 800secure the panel 790 to the support blocks 800, and the support blocks800 hold the panel 790 a predetermined distance or spacing from theskins 770 and 780.

The support blocks 800 extend outwardly from their recesses in the skinsso as to provide a space for air flow between the panel 790 and theadjacent skins. This is clearly shown in FIG. 18. The support blocks 800include ends 804 and 806 which extend into the recesses or bores 776 and786 of the inside and outside skins 770 and 780, respectively.

With the panel 790 secured to and disposed between the skins 760 and 780by the support blocks 800 and their recesses 802, respectively, and withand the skins 760 and 780 secured to the frame 752, the door 750 iscomplete.

A chamber 820 is defined between the skins 760 and 780 and the end 756of the stile 754 and above the bottom rail 762, as shown in FIG. 18. Thechamber 820 extends about the outer periphery 792 of the panel 790 andwithin both stiles and both rails, as may be understood from FIG. 17.

The airflow around the panel 790 is illustrated by the arrows in FIG. 18into and out of the chamber 820, and thus through the door 750 from aroom to the outside of the room, as discussed above for the previousembodiments of the pressure build up prevention doors. The airflow isnon-linear, as with the previous embodiments to prevent pressure buildup in a room.

With the relatively large peripheral length around the entire perimeteror outer periphery of the center panel 792 for the chamber 820, there ismore than adequate area for air flow through the door 750 to preventpressure build up in a room in which the door 750 is located.

It will be noted, as best understood from FIG. 18, that the thickness ofthe panel 790 generally controls the air flow into and out of thechamber 820. The thickness of the panel, preferably centered between theinside and outside skins, determines the spacing between the panel andthe adjacent interior walls of the respective skins. As indicated, thepanel 790 is hatched for glass, and thus is shown as a fixed width. Ifthe panel 790 were to be wood, mdf, etc., it could be tapered in thearea of the openings 778 and 788 of the skins, and thus vary the flow ofair into and out of the chamber 820 from a predetermined amount basedsolely on the fixed thickness of the panel.

While the center panel 790 is hatched for transparent material in FIG.18, it will be understood that any type of material may be used for thepanel. The center panel may also have a different configuration thanshown, and may be of any appropriate size. Moreover, there may be otherways to secure the center panel to the skins than that shown in FIG. 18.

For construction, an inside skin 770 is first prepared and an outer doorframe 752 is placed on the skin. The plurality of support blocks 800 issecured to the center panel 790, and the center panel is then placed onthe inside skin with the ends 804 of the support blocks 800 disposed inthe recesses 776. The outside skin 780 is then placed on the door frame752, with the recess or bores 786 of the outside skin receiving the ends806 of the support blocks to complete the fabrication of the door 750.The several elements are, of course, appropriately secured togetherduring the fabricating or assembly process.

For convenience, and to follow the elements shown in FIG. 18, the terms“inside” and “outside” have been used herein to differentiate the twodifferent sets of support blocks. Actual fabrication, of course, may beas desired with respect to “inside” and “outside,” or even a differentmanufacturing procedure may be used. Moreover, a door may use more thana single panel. For example, a top panel and a bottom panel may be usedfor esthetic purposes.

As with the other pressure build up prevention doors discussed above,scrubbing elements or materials may be added to the door 750 for theremoval of noxious material from the air flow through the door.

FIG. 19 is a schematic view of a portion of a stile and rail door 830having hollow core stiles and rails for providing perimeter air flowthrough the door. The door 830 also includes sensor elements for sensingpredetermined information from the air flow through the door.

The door 830 includes a panel 870 which includes an inside face 872 andan outside face 874. A tongue or flange 876 extends about the outerperimeter of the panel 870, and extends into support elements 890. Thetongue or flange 876 has a reduced thickness relative to the thicknessof the panel 870 for matingly engaging the support elements 890, and forproviding a relatively smooth air flow about the panel 870.

Disposed within the hollow cores of the stiles and rails are the supportelements 890. The support elements 890 are spaced apart about the outerperimeter of the panel 870 for providing appropriate support for thepanel 870 within the chambers defined by the hollow cores of the stilesand rails of the door 830.

The support element 890 includes a pair of oppositely inwardly extendinginside and outside tapers 892 and 894, respectively. The tapers 892 and894 extend to a recess 896. The recess 896 terminates in a flat end. Theflange 876 of the panel 870 extends into the recess 896, with an end 882of the tongue or flange 876 disposed against the end of the recess 896.The support elements 890 are appropriately secured within the hollowcores.

The panel 870 includes an inside face 872 and an outside face 874. Thepanel 870 also includes the tongue or flange 876 extending about thepanel 870. The flange 876 includes tapering portions 878 and 880extending from the faces 872 and 874, respectfully. The tapers 878 and880 reduce the thickness of the flange 876 relative to the thickness ofthe panel 870. The flange 876 terminates in the outer end 882 at theouter perimeter of the panel 870.

The flange 876 is disposed within the recesses 896 of the supportelements 890, with the end 882 of the panel 870 disposed at the innerends of the slots 896 of the elements 890. Thus, the spaced apartsupport elements 890 secure the flange 876 of the panel 870 within thehollow cores of the stiles 832, 840 and rails 850 and 860.

A chamber 900 is defined within the aligned slots or hollow cores of thestiles and rails and about the flange 876. As shown in FIG. 19 by thedouble lined arrows about the flange 876, air flows along or about theinside face 872 of the panel 870 and into the chamber 900, around theend 882 of the tongue or flange 876, out of the chamber 900, and alongor about the outside face 874 of the panel 970 and out of the room inwhich the door 830 is secured.

The chamber 900, defined by the hollow cores of the stiles and railsinto which the air flows through the door 830, to provide the samepressure build up prevention as the air flows through the hollow coredoor 750, shown in FIGS. 10 and 11, discussed above. The structure isdifferent, but the same function is provided. The air flows from theroom, as from the room 400 of FIG. 7, around the outer periphery 876 ofthe panel 870, into the chamber 900, and from the chamber 900 outwardlyfrom the room as shown by the double arrows.

The room air thus flows through the stile and rail door 830 outwardlyfrom the room to prevent the build up of pressure in the room. The flowof air through the door is non-linear to provide a degree of privacywith respect to both light, sight, and sound. The non-linearity isillustrated by the at least five changes of direction in the flow of airthrough the door 830, as with the other doors discussed above.

A sensor/transmitter 1000 is shown in the stile 832. Thesensor/transmitter 1000 includes a sensor probe 1002 extending into thechamber 900. The sensor may be configured to sense any desirableinformation, such as temperature, humidity, occupancy, VOCs, smokeparticulates, carbon monoxide, radon, etc. The information sensed may betransmitted to appropriate receivers, servos, etc. (not shown). The door830 thus may also be considered a smart door, such as the door 650.

With sensors in every room, such as a static or fixed sensor/transmitter403 (see FIG. 7) in one part of a room and another sensor 1002 in adoor, and every room in a home thus equipped, and with the sensedinformation transmitted to a computer, the cloud, or to a smart phone,the status of the air in each room then notes any anomaly. The anomalyis noted and then appropriate action may be taken.

The sensed information pinpoints not only the potential problem, butprovides the specific location of the potential problem. For example,sensors showing higher than normal humidity in a bathroom may indicate aproblem. The specific bathroom is noted. A high radon reading in onepart of a house may indicate a radon leak, and the location of the leakor source is noted. The same situation may occur with VOCs noted in aspecific room. These are just a few examples of the possibilities of theapparatus of the door 830 combined with static sensors in a room.

The door 650 may be considered the first generation “smart door,” andthe door 830 the second generation “smart door,” and a door 1010 may beconsidered the third generation “smart door.” The door 1010 is a hollowcore door with movable dampers for controlling air flow through thedoor.

FIG. 20 is a plan view of the hollow core door 1010 with movable damperpanels secured to a center panel between inside and outside skins. FIG.20 comprises the top or upper half of the door 1010. FIG. 21 is a viewin partial section and partially broken away illustrating the centerpanel secured to the inside and outside skins and the movable damperpanels secured to the center panel. FIG. 21 is taken generally alongline 21-21 of FIG. 20. For the following discussion, reference may bemade to FIGS. 20 and 21.

The hollow core door 1010 includes a frame including a stile 1012, astile 1014 and a top rail 1016. An outside skin 1020 and an inside skin1030 are secured to the stiles and rails of the conventional or standardhollow core door frame.

The outside skin 1020 includes an opening 1022. The opening 1022includes a peripheral recess 1024.

The inside skin 1030 includes an opening 1032 and the opening 1032includes a peripheral recess 1034. As may be understood from FIG. 21,the inside and outside skins 1030 and 1020, respectively, are disposedagainst each other at the inside of the recesses, the inside of therecesses defining inwardly extending rims for the skins of the door1010. The recesses 1024 and 1034 extend about the inner peripheries ofthe respective skins. The skins 1020 and 1030 are mirror images of eachother.

At the juncture line of the interior periphery of the skins, as bestshown in FIG. 21, is a damper groove 1038 which receives the movabledamper panels. The damper groove 1038 extends about the inner peripheryat the juncture of the skins. This will be discussed below.

A center panel 1040 is disposed between the skins 1020 and 1030 in thehollow core of the door 1010. The center panel 1040 is comprised of twohalf panels 1042 and 1052. The half panel 1042 is an outside centerpanel, and the half panel 1052 is an inside center panel. Facing eachother is a recess 1046 and a recess 1056 in the outside center panel1042 and the inside center panel 1052, respectively.

The outside center panel 1042 includes a tapered outer perimeter 1044.The tapered outer perimeter 1044 includes a plurality of spaced aparttabs 1048. The tabs 1048 are disposed on bosses (not shown) of theoutside skin 1020, and are appropriately secured thereto. Between thetabs 1048 are notches 1050. Air flows through the notches 1050 as willbe discussed below. The outside and inside skins include the spacedapart bosses (not shown) on which the tabs are disposed and on whichthey are secured. Both halves of the center panel 1040 include alignednotches. A notch 1050 on the outside half panel 1042 is shown in FIG.21, and may be understood from FIG. 20.

The inside center panel 1052 includes a tapered outer perimeter 1054.The notches 1050 are spaced apart between the tabs 1058. Air flowsthrough the aligned notches 1050 and 1060 on the center panel 1040. Theouter perimeter of the panel halves, and thus of the panel 1040, isgreater than the inner peripheries of the openings in the skins,resulting in a non-linear air flow through the door 1010.

Within the recesses 1042 and 1052 is a damper panel assembly 1070. Thedamper panel assembly 1070 is appropriately secured to the outsidecenter panel 1042. The damper assembly 1070 includes a side damper panel1072, a side damper panel 1074, a top damper panel 1076, and a bottomdamper panel (not shown). The damper panels 1072, 1074, and 1076 areshown in their closed position in FIG. 20, blocking the flow of airthrough the aligned notches 1050 and 1060.

The damper panel 1072 is shown in its open position in FIG. 21, allowingair to flow through the aligned notches and through the door 1010. Theflow of air may be understood from FIG. 21 to be non-linear.

In FIG. 20, the movement of the damper panels is accomplished by thedamper panel assembly 10 70. An actuator bar 1080 is movable verticallyon the panel, and is biased in its upper position by a tension spring orsprings (not shown) to keep the damper panels in their closed position,as shown in FIG. 20.

Downward movement of the actuator bar 1080 moves the damper panels totheir open position, as shown in FIG. 21. The damper panels areconnected to the bar 1080 through actuator plates or bell cranks androds.

An upper actuator plate or bell crank 1086 is secured to the bar 1080for pivoting movement. The bell crank 1086 is a T-shaped bell crankwhich pivots on the bar 1080 in response to vertical movement of the bar1080. In turn, the bell crank 1086 is pivotly secured to the outsidecenter panel 1042. The bottom of the tee is secured to the bar 1080,while the center of the arms is pivotly secured to the panel 1040. Thearms of the bell crank 1086 are pivotly secured to the damper panel 1072and to the damper panel 1074 by rods 1088 and 1090, respectively.

Rods 1094 and 1096 are pivotly secured to the arms of a bell crank 1092.As the bar 1080 moves downwardly, the bell cranks 1086 and 1092 pivotcounterclockwise and draw their respective rods inwardly, thus movingthe side plates 1072 and 1074 inwardly to uncover the notches 1050 and1060 to allow air flow through them, as shown in FIG. 21.

Thus vertical movement of the bar 1080 results in the joint inwardly andoutwardly movement of the damper panels to control air flow through thealigned notches 1050 and 1060 of the two halves 1042 and 1052 of thecenter panel 1040, respectively.

The top and bottom damper panels respectively, move jointly with theside damper panels by means of angle arms secured to the side panels andto the outside center panel 1040.

The top damper panel 1076 moves by an angle plate 1100 and an angleplate 1110, both of which are secured for pivoting on the outside centerpanel 1042 at the juncture of the angle arms. The plate 1100 is pivotlysecured to the side damper plate 1072 by a rod 1102 and to the topdamper plate by a rod 1104. The rods 1102 and 1104 are secured to theplate 1100 at the outer ends, respectively, of the bottom and top of thearms of the angle plate 1100.

The angle plate 1110 is pivotly secured to the outside center panel 1042at the juncture of its arms, and to the top damper plate 1076 by a rod1110 and to the side damper plate 1020 by a rod 1112. The rods 1110 and1112 are secured to the arms of the plate 1110 at the outer ends of thetop and bottom arms, respectively.

As the side damper panels 1072 and 1074 move inwardly by the upwardmovement of the bar 1080, the respective angle plates pivot to move thetop and bottom damper plates outwardly to block air flow through thealigned notches 1050 and 1060. As the bar 1080 moves downwardly to movethe side damper panels inwardly, the angle plates pivot to move the topand bottom plates to move inwardly to allow air movement through thenotches 1050. The movement of the damper plates is jointly orsimultaneously to control the flow of air through the aligned notches1050 and 1060 through the center panel 1040.

Movement of the bar 1080 is controlled by an actuator 1152. The actuator1152 is disposed in a removable housing or tray 1150 located in the toprail 1016. Also disposed in the housing 1150 is a sensor package 1154,with a plurality of sensors and transmitters and a microprocessorcomputer, and an appropriate power source, such as a battery pack 1156,for providing power for the actuator 1152 and the sensor package 1154.It will be noted that any appropriate power transfer device may be usedto move the damper panels.

Under microprocessor computer control, the bar 1080 may be movedincrementally to control the flow of air through the door 1010. With anumber of such doors in a dwelling, the air flow through the doors maybe closely matched to the requirements for the precise balancing of airflow throughout a dwelling for maximum efficiency of a forced air systemregardless of temperature, wind, or other factors. Sensors for sensingair flow, temperature, humidity, smoke or other particulates, or anyother desired elements or quantities, as discussed previously, may beconsidered when programming microprocessors for the control of airthrough a pluralities of doors in a dwelling.

A microprocessor computer may correlate the sensed informationtransmitted by a plurality of sensors in the plurality of doors andtransmit signals to control the flow of air through a plurality of doorsto prevent the pressure build up in the rooms in which the doors areinstalled, and thus maintain the desired pressure in each room at orbelow the recommended three pascals, as set forth above.

Moreover, with the technology of smart phones and appropriate apps, theinformation as to pressure or any other desired data may be transmittedand signals may be transmitted for remotely controlling air flow. Theincremental adjustment of the damper panels allows precise control ofair flow through a plurality of doors in a dwelling or other structureaccording to predetermined parameters or by selective remote controlthrough smart phone technology.

As best shown in FIG. 21, a chamber 1066 is defined within theperipheral recesses 1024 and 1034 of the outside and inside skins,respectively, into and out of which chamber the air flows. The chamber1066 extends fully about the center panel 1040. The outer portion of thepanel 1072 extends into the chamber 1066. The damper panels, such as thepanels 1072, 1074, and panel 1076 shown in FIG. 20, control the flow ofair around or about the perimeter of the panel 1072 and thus through thedoor 1010 in a non-linear manner of a least five changes of direction inthe air flow.

The size and number of the notches may be varied to provide thenecessary air flow. It is the air flow that is important, not the numberof notches. Moreover, while the above discussion refers to structureswith a forced air system, the present invention applies to theprevention of pressure buildup regardless of the source of airflow intoa room, such as a forced air system shown in FIG. 7 or an open window(not shown).

FIG. 22 is a plan view, partially broken away, of a hollow core doorembodiment 1200 of the present invention. FIG. 23 is a view in partialsection taken generally along line 23-23 of FIG. 2. FIG. 24 is a view inpartial section taken generally along line 24-24 of FIG. 22. For thefollowing discussion, reference will be made primarily to FIGS. 22, 23,and 24.

The door 1200 has a conventional hollow core door frame including a pairof stiles, of which a stile 1202 is shown in FIG. 23, and a pair ofrails, of which a top rail 1206 is best shown in FIG. 24. The stiles andrails are appropriately secured together.

A center element comprising a pair of molded skins is secured to thestile and rail frame. The skins include an inside skin 1210 and anoutside skin 1212. Filler material 1204 is shown disposed between theskins 1210 and 1212 in FIG. 23. The molded skins 1210 and 1212 includeinwardly tapered portions 1208, which are well known and understood inthe art.

Spaced apart along the skins adjacent to the frame are holes or openings1214. The holes or openings 1214 extend through the molded skinsadjacent to the tapered portions 1208 of the stiles and rails,respectively. The area or portion of the molded skins at or adjacent tothe tapered portions 1208 is defined as the margins of the door 1200.

FIG. 23 shows the stile 1202 and the molded inside and outside skins1210 and 1212, respectively, adjacent to the opening 1214.

FIG. 24 shows the location of an opening 1214 through the skins 1210 and1212 and adjacent to the rail 1206 at the margins of the door 1200. Seealso FIG. 22.

On top of the inside skin 1210 is an outer inside skin or cover 1220.The outer inside skin or cover 1220 includes an opening 1222. Theopening 1222 is located laterally inwardly from the openings 1214through the inside and outside skins 1210 and 1212, respectively.

On top of the outside skin 1212 is an outer outside skin 1224. The outeroutside skin 1224 includes an opening 1226. The opening 1226 is adjacentto and spaced apart laterally inwardly from the openings 1214. With theopenings 1222 and 1226 spaced apart laterally inwardly from the openings1214, the flow of air through the door 1200 is non-linear, with at leastfive changes of direction in the flow of air.

As best shown in FIG. 24, the air flow through the door 1200 is throughthe opening 1222 in the outer inside skin or frame 1220, through theopening 1214, along the outside skin 1212, and outwardly through theopening 1226 in the outer outside skin 1224. As may be understood by thecurved arrow in FIG. 24, the air flow through the door 1200 isnon-linear, with at least five changes of direction. This non-linear airflow pattern is also present in the prior art doors discussed above.

The openings 1222 and 1226 are aligned generally parallel to each other.This alignment is shown clearly in FIGS. 23 and 24.

FIG. 25 is a plan view, partially broken away, of a stile and rail doorembodiment 1240 of the present invention. FIG. 26 is a view in partialsection through a stile 1244 taken generally along line 26-26 of FIG.25. FIG. 27 is a view in partial section through a top rail 1246 takengenerally along line 27-27 of FIG. 25. For the following discussion,reference may be made to FIGS. 25, 26, and 27.

The door 1240 includes a conventional stile and rail frame 1242, ofwhich a stile 1244 and a top rail 1246 are shown in FIG. 25. The stilesof the frame 1242 are illustrated as engineered stiles, with a solidwood outer element and a plurality of plywood elements secured to thewood element. The purpose of the engineered stiles is to reduce warpingof the door. The rails are generally solid wood, since warping is not aproblem for the rails. The stiles and rails are appropriately securedtogether to comprise a frame.

Laminates 1254 and 1256 are shown secured to the stile 1244. Laminates1258 and 1259 are shown secured to the rail 1246. The laminates coverthe stiles and the rails for esthetic purposes.

On the inside perimeter of the stiles and rails of the frame 1242 is aconventional ovolo sticking 1248. The ovolo sticking is best shown inFIG. 26. There is a groove or slot 1252 centered in the ovolo sticking1248. The groove or slot 1252 receives the outer perimeter of a centerelement or panel 1260

The center panel 1260 is secured to the stile and rail frame 1242 in thegroove 1252 at a reduced thickness outer perimeter portion 1262. Thereduced thickness outer perimeter portion 1262 includes a tapered insideportion 1264 and a tapered outside portion 1266. The reduced thicknessouter perimeter portion 1262 terminates in an outer end 1268. The end1268 and an adjacent part of the reduced thickness outer perimeterportion 1262 extend into the groove or slot 1252 of the sticking 1248and is appropriately secured therein.

The ovolo sticking 1248 and the adjacent portion of the reducedthickness outer perimeter 1262 define the margin portion of the door1240, through which extends a plurality of spaced apart openings 1270.That is, the juncture of the sticking and the center panel define themargin of the door 1240.

An inside skin element or cover 1280 is disposed about the stiles andrails of the frame 1242. The inside skin element or cover 1280 includesan opening 1282. The opening 1282 is located laterally inwardly relativeto the openings 1270 to provide the non-linear flow of air through thedoor 1240.

An outside skin element or cover 1290 is disposed about the stiles andrails of the frame 1242 generally parallel to an inside skin or cover1280. The outside frame or cover 1290 includes an opening 1292 which isaligned generally parallel to the opening 1282 of the skin or cover1280. This is clearly shown in FIGS. 26 and 27.

In the stile and rail door 1240, the inside and outside skin elements1280 and 1290 are essentially outer inside and outer outside elements.

The openings 1282 and 1292 are disposed adjacent to and spaced laterallyinwardly from the openings 1270 at the margins of the door 1240 toprovide a non-linear path for the air flow through the door.

As may be understood from FIG. 27, air flow through the door 1240 flowsabout the opening 1282 in the skin 1280 and past the tapered portion1264 of the outer perimeter reduced thickness portion 1262 of the centerframe 1260. The air then flows through the openings 1270 and around thereduced thickness portion 1262, past the outside tapered portion 1266.The air then flows outwardly through the opening 1292 of the outsideskin or frame 1290. The air flow is in a non-linear manner, as indicatedby the arrow in FIG. 27 to help control light, sight, and sound throughthe door. The non-linear air flow also, as with the previously discusseddoors, has at least five changes of direction.

Referring again to FIGS. 22 and 24 and to FIGS. 25 and 27, a marginperiphery may be defined by the openings 1214 and 1270 for the doors1200 and 1240, respectively. That is, with the openings 1214 and 1270disposed all around the doors 1220 and 1240, the openings 1214 and 1270define a margin periphery with respect to air flow through the doors. Amargin periphery has a margin peripheral length defined by the openingsthrough which air flows into the doors. In other words, the length of aline drawn through the openings in the margins of a double skin door andof a stile and rail door define a margin peripheral lengths.

The length of the inner periphery of an opening in the outer skins of adouble skin door, and the length of the inner periphery of an opening ofthe skins in the stile and rail door, define the a skin openingperipheral lengths.

For any door, a margin peripheral length is greater than a skin openingperipheral length. Accordingly, the air flow through a door isnon-linear since the air must flow through the openings in the insideskin, about the center element and outwardly through the opening in theoutside skin. This path through the door requires at least five changesof direction in the flow of air.

The general principles of the structure of the doors 1200 and 1240 maybe applied to a wide variety of decorative geometric designs in theouter skins or covers. FIG. 28 is a view in partial section through adoor 1300, comparable to FIG. 23 for the door 1200. The door 1300 is ahollow core door with openings extending through outer inside andoutside skins inwardly of the margins shown in FIGS. 23 and 24. Theopenings are decorative geometric or pattern openings in the outerinside and outside skins.

The door 1300 includes a conventional stile and rail frame such asdiscussed above for other hollow core doors discussed above. The door1300 has a stile 1302 and a molded inside skin 1310 and a molded outsideskin 1320. The molded skins 1310 and 1320 include inwardly extendingtapered portions 1312, with filler material 1308 disposed between theskins, as discussed above and as is well known and understood in thehollow core door manufacturing art. Openings 1312 extend through theskins 1310 and 1320 at the margins of the door as discussed above forthe door 1200.

An outer inside skin or cover 1330 is appropriately secured to theinside skin 1310, and an outer outside skin 1340 is appropriatelysecured to the outside skin 1320. The outer skins 1330 and 1340 includea decorative design or pattern which includes a plurality of openings,such as openings 1332 and 1334 for the outer skin 1330 and openings 1342and 1344 for the outer skin 1340.

A plurality of support blocks 1348 and 1350 are shown extending betweenthe inside and outside skins 1310 and 1320, respectively, and the outerskins or covers 1330 and 1340, respectively, for supporting thedecorative design or pattern elements.

The spacer blocks 1348 and 1350 are comparable to other spacer blocksdiscussed above, such as the spacer blocks 444 for the door 410 of FIG.8, and the spacer blocks 674 and 724 for the door 650 of FIGS. 12 and 13for providing appropriate support.

The decorative geometric pattern or design is cut into both outer skinsor covers and the patterns may be appropriately aligned in parallel. Airflows into the door 1300 through the design openings, such as theopenings 1332 and 1334 in the outer inside skin, around the spacerblocks, and through the openings 1312 and outwardly from the doorthrough the pattern openings 1342 and 1344 in the outer outside skin1340. The air flow through the door 1300 is non-linear, with at leastfive changes of direction, as discussed for the other doors discussedabove.

The design or pattern cut into the outer skins may be virtually anyconfiguration, from something relatively simple such as a circle, anoval, a diamond, or something relatively complicated, such as a tree.The limit is a person's imagination. Fragmentary examples of suchdesigns are shown in FIGS. 29, 30, and 31.

FIG. 29 is a fragmentary plan view a simple circle or oval geometricdesign. The circle, or circles, or ovals, may be located as desired inthe outer skins or covers of a door subject to the requirement that airflow through the outer skins is non-linear.

FIG. 30 is a fragmentary plan view of a simple diamond geometric design.The diamond, or diamonds, may be located as desired in the outer skinsor covers of a door.

FIG. 31 is a fragmentary view of a more complicated geometric designthan the designs of FIGS. 29 and 30. The design shown is a tree design.The tree, or trees, may be located as desired in the outer skins orcovers of a door.

Moreover, rather than have the same design on both sides of a door, andgenerally parallel to each other, different designs may be used in theinside and outside of a door. As with all doors, the air flow desiredthrough the door must be matched to the size of the openings in theinside and outside door elements.

The design principles of the door 1300 and the use of decorativeelements in the outer panels or skins with the support elements as shownin FIG. 28, may also be applied to a stile and rail door such as thedoor 1240, as indicated above. The skins 1280 and 1290 may includedecorative designs along with the use of the support blocks as shown inFIG. 28. The decorative design openings, such as shown in FIGS. 29, 30,and 31, or other desired designs, may be cut in the outer skins toprovide the desired air flow through the door.

As with the other doors discussed herein, appropriate material may beadded to the inside of the door 1010 for removing noxious material fromthe air flow through the door.

While the principles of the invention have been made clear inillustrative embodiments, there will be immediately obvious to thoseskilled in the art many modifications of structure, arrangement,proportions, the elements, materials, and components used in thepractice of the invention, and otherwise, which are particularly adaptedto specific environments and operative requirements, without departingfrom those principles. For example, the cuts through the center elementsmay be located as desired with respect to the stiles and rails.Moreover, the definition of “margins” may be varied as desired for aparticular application for hollow core doors and stile and rail doors.The margins need not be at the inwardly tapering portion of a moldedskin of a hollow core door, but may be located at any desired orconvenient position. This is especially true for geometric decorativedesigns. The appended claims are intended to cover and embrace any andall such modifications, within the limits only of the true spirit andscope of the invention.

What I claim is:
 1. A door having a stile and rail frame and a centerelement secured to the stile and rail frame for preventing pressurebuild up in a closed room comprising in combination: a pair of stilesspaced apart; a pair of rails, including a top rail and a bottom railsecured to the spaced apart stiles and defining a door frame; a centerelement secured to the door frame; margins of the door frame and thecenter element defined as the portions of the door frame and the centerelement adjacent to where the door frame and the center element overlap;openings extending through the margins of the door frame and the centerelement; an inside skin secured to the door frame and having an openingadjacent to and laterally inwardly from the openings through the marginsof the door frame and the center element; and an outside skin secured tothe door frame and having an opening adjacent to and laterally spacedapart from the openings through the margins of the door frame and thecenter element, whereby air flows through the opening in the insideskin, through the openings through the margins and through the openingin the outside skin in a non-linear manner to prevent pressure build upin the closed room.
 2. The door of claim 1 in which the door comprises ahollow core door and the center element comprises a first pair of skinssecured to the door frame.
 3. The door of claim 2 in which the firstpair of skins includes a molded inside skin and a molded outside skinand the molded inside and outside skins taper inwardly and the marginsof the door frame and the center element are defined at the inwardtapers.
 4. The door of claim 3 in which the openings in the inside andoutside skins extend through the margins at the inward tapers.
 5. Thedoor of claim 4 which further includes a second pair of skins, includingan outer inside skin and an outer outside skin, and the outer insideskin and the outer outside skin include openings through which air flowsto and through the openings in the margins.
 6. The door of claim 5 inwhich the openings in the second pair of skins comprise decorativedesigns, and further includes support elements for supporting the outerinside skin and the outer outside skin adjacent to the decorative designopenings.
 7. The door of claim 1 in which the door is a stile and raildoor and the center element is a center panel having margins adjacent tothe stiles and rails, and the openings extend through the margins of thestiles and rails and the center panel.
 8. The door of claim 7 in whichthe stile and rail door includes laminates secured to the pairs ofstiles and rails.
 9. The door of claim 8 in which the openings extendthrough the laminates.
 10. The door of claim 1 in which the openings inthe inside and outside skins are aligned.
 11. The door of claim 1 inwhich the openings in the inside and outside skins have an innerperipheral length and the door frame and center element have a marginperipheral length which is greater than the inner peripheral length. 12.The door of claim 1 which includes means for removing noxious materialfrom the air flow through the door.
 13. The door of claim 1 in which thestiles and rails include a sticking, a groove in the sticking; and thecenter element includes an outer perimeter extending into the groove inthe sticking.
 14. The door of claim 13 in which the plurality ofopenings in the center element extend through the sticking and the outerperimeter of the center element in the sticking.
 15. The door of claim14 in which the margins of the door frame and the center element aredefined at the juncture of the sticking and the center element.
 16. Adoor having a stile and rail frame and a center element secured to thestile and rail frame for preventing pressure build up in a closed roomcomprising in combination: a pair of stiles spaced apart; a pair ofrails secured to the spaced apart stiles and defining a door frame; acenter element secured to the door frame; an inside skin secured to thedoor frame; an opening extending through the inside skin; an outsideskin secured to the door frame; an opening extending through the outsideskin; the door frame and the center element having margins defined wherethe door frame and the center element overlap and openings extendingthrough the margins spaced apart outwardly from the openings in theinside and outside skins whereby air flows non-linearly through theopenings in the inside skin, through the margin openings in the centerelement, and outwardly through the opening in the outside skin.
 17. Thedoor of claim 16 in which the stiles and rails include a sticking, andthe openings at the margins extend through the sticking.
 18. The door ofclaim 16 in which the stiles and rails include a sticking, and thecenter element is secured to the door frame at the sticking.
 19. Thedoor of claim 18 in which the sticking includes a groove and the centerelement includes an outer perimeter portion which extends into thegroove.
 20. The door of claim 16 in which the openings in the inside andoutside skins include decorative patterns and support elements forsupporting the inside and outside skins adjacent to the decorativepattern openings.
 21. The door of claim 16 which further includes meansfor removing noxious material from the flow of air through the door.